Indoor global position system (GPS) embedded in lighting systems have recently been promoted as emerging technology by major electronics/lighting companies such as Philips Lighting and General Electric (GE). In 2016, Philips Lighting describes in its “Philips Indoor Positioning White Paper” a concept of using Visual Light Communication (VLC) of Light-emitting Diode (LED) lighting systems for indoor GPS application. In their proposal, each Philips light fixture can send a unique identification code using VLC, referring to FIG. 1. The shoppers can use the camera of their mobile phones to receive such codes. Therefore, the indoor lighting system can communicate with the shoppers in a building through VLC and provide a range of services such as shopping guidance, position instructions etc for the shoppers. A unique feature is that direct visual light is essential in this indoor GPS systems.
General Electric and a company called AcuityBrands market their Indoor Positioning System using VLC of LED lighting systems and Bluetooth technology. This concept can be illustrated through a trademark ByteLight as shown in FIG. 2. Similarly to the Philips' approach, they use VLC to locally locate and communicate with the shopper with a mobile phone. Then through the Bluetooth communication, the shopper can obtain or listen to the product information. GE in their website claims that such system can also be used in Museums to provide for the visitors the introductions and details of the items of interests when the visitors approach them.
The three technologies suggested by Philips Lighting, GE and AcuityBrands share the same common technology of VLC using LED lighting systems. GE and Acuity offer the extra use of Bluetooth to provide an extra channel of communication of product or service information. However, the use of VLC and Bluetooth have some major limitations. Firstly, the mobile communication devices of the shoppers, such as the mobile phones or smart watches of the shoppers, must be under direct light from the LED system. If the mobile phones are in the handbags of the shoppers, VLC cannot communicate with shoppers. This issue may not be a major problem if the applications are restricted to the cases that the shoppers must hold their mobile communication devices in their hands. But this issue will be a major limitation if the application is needed to expand to other areas such as counting the number of the people and monitoring the flow of people whose mobile communication devices are not under direct light of the lighting system. Secondly, the communication range of Bluetooth is relatively short, typically 10 meters. For large buildings with tall ceilings such as airports, the use of Bluetooth may not be appropriate.